Many features of posttraumatic stress disorder (PTSD) can be linked to exaggerated and dysregulated emotional responses. Central to the neurocircuitry regulating emotion are functional interactions between the amygdala and the ventromedial prefrontal cortex (vmPFC). Findings from human and animal studies suggest that disruption of this circuit predicts individual differences in emotion regulation. However, only a few studies have examined amygdala-vmPFC connectivity in the context of emotional processing in PTSD. The aim of the present research was to investigate the hypothesis that PTSD is associated with disrupted functional connectivity of the amygdala and vmPFC in response to emotional stimuli, extending previous findings by demonstrating such links in an understudied, highly traumatized, civilian population. 40 African-American women with civilian trauma (20 with PTSD and 20 non-PTSD controls) were recruited from a large urban hospital. Participants viewed fearful and neutral face stimuli during functional magnetic resonance imaging (fMRI). Relative to controls, participants with PTSD showed an increased right amygdala response to fearful stimuli (pcorr<.05). Right amygdala activation correlated positively with the severity of hyperarousal symptoms in the PTSD group. Participants with PTSD showed decreased functional connectivity between the right amygdala and left vmPFC (pcorr <.05). The findings are consistent with previous findings showing PTSD is associated with an exaggerated response of amygdala-mediated emotional arousal systems. This is the first study to show that the amygdala response may be accompanied by disruption of an amygdala-vmPFC functional circuit that is hypothesized to be involved in prefrontal cortical regulation of amygdala responsivity.

Background Post-traumatic stress disorder (PTSD) develops in a minority of traumatized individuals. Attention biases to threat and abnormalities in fear learning and extinction are processes likely to play a critical role in the creation and/or maintenance of PTSD symptomatology. However, the relationship between these processes has not been established, particularly in highly traumatized populations; understanding their interaction can help inform neural network models and treatments for PTSD. Method Attention biases were measured using a dot probe task modified for use with our population; task stimuli included photographs of angry facial expressions, which are emotionally salient threat signals. A fear-potentiated startle paradigm was employed to measure atypical physiological response during acquisition and extinction phases of fear learning. These measures were administered to a sample of 64 minority (largely African American), highly traumatized individuals with and without PTSD. Results Participants with PTSD demonstrated attention biases toward threat; this attentional style was associated with exaggerated startle response during fear learning and early and middle phases of extinction, even after accounting for the effects of trauma exposure. Conclusions Our findings indicate that an attentional bias toward threat is associated with abnormalities in ‘ fear load ’ in PTSD, providing seminal evidence for an interaction between these two processes. Future research combining these behavioral and psychophysiological techniques with neuroimaging will be useful toward addressing how one process may modulate the other and understanding whether these phenomena are manifestations of dysfunction within a shared neural network. Ultimately, this may serve to inform PTSD treatments specifically designed to correct these atypical processes.

Introduction Impaired inhibition of fear in the presence of safety cues and a deficiency in the extinction of fear cues are increasingly thought to be important biological markers of Posttraumatic Stress Disorder (PTSD). Other studies have suggested that there may be altered neural activation during behavioral inhibition tasks in subjects with PTSD. The current study aimed to see whether neural activation during inhibition was reduced in a highly traumatized civilian population, and whether atypical activation was associated with impaired fear inhibition. Methods The participants were 41 traumatized women (20 PTSD+, 21 PTSD−) recruited from Grady Memorial Hospital in Atlanta, GA. We used a Go/NoGo procedure with functional magnetic resonance imaging (fMRI) in a high-resolution 3T scanner. Participants were instructed to press a button whenever an “X” or “O” appeared on the screen, but not if a red square appeared behind the letter. Participants were assessed for trauma history and PTSD diagnosis, and completed a fear-potentiated startle and extinction paradigm. Results We found stronger activation in the ventromedial prefrontal cortex (vmPFC) in traumatized subjects without PTSD compared to those with PTSD in the NoGo greater than Go contrast condition. Activation in the vmPFC was negatively correlated with fear-potentiated startle responses during safety signal learning (p=.02) and fear extinction (p=.0002). Conclusions These results contribute to understanding of how the neural circuitry involved in inhibitory processes may be deficient in PTSD. Furthermore, the same circuits involved in behavioral inhibition appear to be involved in fear inhibition processes during differential fear conditioning and extinction.

Prior structural imaging studies of post-traumatic stress disorder (PTSD) have observed smaller volumes of the hippocampus and cingulate cortex, yet little is known about the integrity of white matter connections between these structures in PTSD samples. The few published studies using diffusion tensor imaging (DTI) to measure white matter integrity in PTSD have described individuals with focal trauma rather than chronically stressed individuals, which limits generalization of findings to this population; in addition, these studies have lacked traumatized comparison groups without PTSD. The present DTI study examined microstructural integrity of white matter tracts in a sample of highly traumatized African-American women with (n ¼ 25) and without (n ¼ 26) PTSD using a tract-based spatial statistical approach, with threshold-free cluster enhancement. Our findings indicated that, relative to comparably traumatized controls, decreased integrity (measured by fractional anisotropy) of the posterior cingulum was observed in participants with PTSD (po0.05). These findings indicate that reduced microarchitectural integrity of the cingulum, a white matter fiber that connects the entorhinal and cingulate cortices, appears to be associated with PTSD symptomatology. The role of this pathway in problems that characterize PTSD, such as inadequate extinction of learned fear, as well as attention and explicit memory functions, are discussed.

Objective A growing body of research focuses on the development and correlates of emotion dysregulation, or deficits in the ability to regulate intense and shifting emotional states. Current models of psychopathology have incorporated the construct of emotion dysregulation, suggesting its unique and interactive contributions, along with childhood disruptive experiences and negative affect, in producing symptomatic distress. Some researchers have suggested that emotion dysregulation is simply a variant of high negative affect. The aim of this study was to assess the construct and incremental validity of self-reported emotion dysregulation over and above childhood trauma and negative affect in predicting a range of psychopathology. Method Five hundred thirty individuals aged 18 to 77 years (62% female) were recruited from the waiting areas of the general medical and obstetric/gynecologic clinics in an urban public hospital in Atlanta, Georgia. Participants completed a battery of self-report measures obtained by interview, including the Childhood Trauma Questionnaire, the Positive and Negative Affect Schedule, and the Emotion Dysregulation Scale. Regression analyses examined the unique and incremental associations of these self-report measurements of childhood traumatic experiences, negative affect, and emotion dysregulation with concurrent structured interview–based measurements of psychiatric distress and history of self-destructive behaviors. These measures included the Clinician-Administered PTSD Scale, the Alcohol Use Disorders Identification Test, the Short Drug Abuse Screening Test, the Beck Depression Inventory, and the Global Adaptive Functioning Scale from the Longitudinal Interval Follow-Up Evaluation. The presented data were collected between 2005 and 2009. Results Regression models including age, gender, childhood trauma, negative affect, and emotion dysregulation were significantly (P ≤ .001) associated with each of the study’s criterion variables, accounting for large portions of the variance in posttraumatic stress symptoms (R2 = 0.21), alcohol and drug abuse (R2 = 0.28 and 0.21, respectively), depression (R2 = 0.55), adaptive functioning (R2 = 0.14), and suicide history (omnibus χ2 = 74.80, P < .001). Emotion dysregulation added statistically significant (P < .01) incremental validity to each regression model (β = 0.25, 0.34, 0.35, 0.34, and −0.18, and Wald = 24.43, respectively). Conclusions Results support the conceptualization of emotion dysregulation as a distinct and clinically meaningful construct associated with psychiatric distress that is not reducible to negative affect. Emotion dysregulation is a key component in a range of psychiatric symptoms and disorders and a core target for psychopharmacologic and psychosocial treatment interventions.

Attentional biases have been proposed to contribute to symptom maintenance in Posttraumatic Stress Disorder (PTSD), although the neural correlates of these processes have not been well defined; this was the goal of the present study. We administered an attention bias task, the dot probe, to a sample of 37 (19 control, 18 PTSD+) traumatized African-American adults during fMRI. Compared to controls, PTSD+ participants demonstrated increased activation in the dorsolateral prefrontal cortex (dlPFC) in response to threat cue trials. In addition, attentional avoidance of threat corresponded with increased ventrolateral prefrontal cortex (vlPFC) and dorsal anterior cingulate cortex (dACC) activation in the PTSD group, a pattern that was not observed in controls. These data provide evidence to suggest that relative increases in dlPFC, dACC and vlPFC activation represent neural markers of attentional bias for threat in individuals with PTSD, reflecting selective disruptions in attentional control and emotion processing networks in this disorder.

We have recently found higher circulating levels of pituitary adenylate cyclase-activating polypeptide (PACAP) associated with posttraumatic stress disorder (PTSD) symptoms in a highly traumatized cohort of women but not men. Furthermore, a single nucleotide polymorphism in the PACAP receptor gene ADCYAP1R1, adenylate cyclase activating polypeptide 1 receptor type 1, was associated with individual differences in PTSD symptoms and psychophysiological markers of fear and anxiety. The current study outlines an investigation of individual differences in brain function associated with ADCYAP1R1 genotype. Forty-nine women who had experienced moderate to high levels of lifetime trauma participated in a functional MRI task involving passive viewing of threatening and neutral face stimuli. Analyses focused on the amygdala and hippocampus, regions that play central roles in the pathophysiology of PTSD and are known to have high densities of PACAP receptors. The risk genotype was associated with increased reactivity of the amygdala and hippocampus to threat stimuli and decreased functional connectivity between the amygdala and hippocampus. The findings indicate that the PACAP system modulates medial temporal lobe function in humans. Individual differences in ADCYAP1R1 genotype may contribute to dysregulated fear circuitry known to play a central role in PTSD and other anxiety disorders.fMRI | emotion | intermediate phenotype | single nucleotide polymorphism P osttraumatic stress disorder (PTSD) is an anxiety disorder estimated to affect 7% of the population (1), with symptoms that are highly debilitating and associated with a range of major physical health conditions (2, 3). PTSD disproportionally affects women over men (1, 4), and mechanisms for this sex difference have not yet been defined. We recently identified a single nucleotidepolymorphism (SNP) in the gene coding for the pituitary adenylate cyclase-activating polypeptide (PACAP) receptor (ADCYAP1R1, adenylate cyclase activating polypeptide 1 receptor type 1) that predicts PTSD in women and not men (5-9). This SNP, rs2267735, is located on a canonical estrogen response element, indicating that estrogen levels may influence expression of the receptor. The ADCYAP1R1 polymorphism has been shown to predict exaggerated arousal responses characteristic of PTSD in autonomic psychophysiology (5, 10), but no study has yet examined the extent to which this polymorphism influences fear responses in the human brain. The current study tests the hypothesis that ADCYAP1R1 polymorphism influences brain regions that underlie emotional arousal, using functional MRI (fMRI) in a sample of women who have experienced civilian trauma.PTSD symptom clusters include hyperarousal, reexperiencing, avoidance, and numbing (11). Recently, evidence has accumulated to support the idea that hyperarousal is predictive of PTSD after trauma, whereas other symptoms are products of the disorder (12). In particular, pretrauma reactivity of the amygdalaa brain region responsible for coordinating and mainta...

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